1. Field
The present invention relates generally to communication systems and more specifically to decision feedback equalizers (DFE) for code decision multiplexed (CDM) signals.
2. Background
Decision feedback filters (DFEs) are often used to improve reception of data by applying equalization to a wireless channel. Based on demodulated data symbols, a filter is adjusted to counteract the effects of a wireless channel. A typical DFE for a single carrier signal includes a feed forward filter and a feedback filter that is based on the output of a symbol level demodulator. Unfortunately, conventional DFEs as applied to code division multiplexing systems result in chip level demodulation that is unreliable since the decisions do not take advantage of the CDM processing gain.
Therefore, there is a need for a DFE for CDM signals.